The invention relates to a port-controlled two-stroke internal combustion engine with a piston having a crosshead movable therewith and a connecting rod extending between the crosshead and a crankshaft for transferring motion from the piston to the crankshaft.
A port-controlled two-stroke internal combustion engine of this type is already known (KSZ 90/160 of MAN) from the German book "Gestaltung und Hauptabmessungen der Verbrennungskraftmaschine", Harald Maass, Springer Publishing Co., 1979, p. 214, FIG. 5,62'. The crosshead engine has an engine block with a crankcase and a cylinder block with a cylinder in which a piston acts on a crankshaft by way of a crosshead rod, a crosshead with crosshead guide and a connecting rod. Between the crankcase and the cylinder block there is a partition which includes a sleeve protruding into the cylinder from the crankcase. In the bottom dead center region of the piston, the piston skirt is partially received between the outer contour of the sleeve and the inner contour of the cylinder.
For general background, reference is made to German Patent Specification 33 27 225 and German Offenlegungsschrift DOS 32 06 152.
A disadvantage of internal combustion engines this type is their large design height because, in this respect, the three heights of the piston stroke, the crosshead stroke and the piston height are normally additive. In addition, the piston skirt is relatively long in the case of port-controlled two-stroke internal combustion engines because, in the upper dead center position of the piston, it must be able to cover and close the ports located in the bottom dead center region of the piston.
In addition to the cost disadvantages resulting from the large design height, there are weight and space disadvantages and these are particularly serious in the case of passenger car engines.
A further disadvantage of internal combustion engines of this type are the large oscillating masses because, due to the large design height, the crosshead rod and the connecting rod have also to be made relatively long and therefore are relatively heavy.
In internal combustion engines of the generic type, furthermore, the rigid connection between the piston and the crosshead rod is a disadvantage because the rigid connection demands exact alignment of the piston guide with the sliding guide track of the crosshead. In the case of large diesel engines, which are produced in small numbers by individual manufacture, this alignment is achieved by matching the cooperating members for each individual cylinder. However, matching of the cooperating members (piston and crosshead guide) or each cylinder individually is too expensive for engines which are manufactured by mass production procedures.
It is therefore the principal object of the invention to provide an internal combustion engine of the described type with the smallest possible design height and lowest possible weight which can be manufactured in a simple manner and at favorable costs.